lawsoniana – named for Charles Lawson (1794-1873), a Scottish nurseryman who specialized in grass seeds and conifers

• he grew trees from seed sent to him in 1854 by William Murray while working on his “Notes on California Trees”

Native range: Western N. America

Leaves:

• scale-like
• closely appressed
• white “Y” or “X” mark on underside
• laterals much larger than facials

Cones:

• “soccer ball”
• small cone – 1/3” across, mature in a single season
• scales decussate
• male cones red, .25” in spring

Other characteristics:

• grayish bark

Relevant info:

• varies in growth form from shrub to tree w/ pyramidal growth to 200 ft.
• in cultivation, reaches half height of the native
• can live 600 years
• leaf scent not as sweet as Thuja, but sweeter than close relative Alaska yellow cedar (Callitropsis nootkatensis, formerly Chamaecyparis nootkatensis)
• wood is commercially valuable, in part because of its ability to resist rot
  • species has suffered negative impact from timber industry
• susceptible to non-native root rot fungus (Phytophthora lateralis) in U.S., which threatens survival of remaining stands
• known in England & Europe as Lawson’s Falsecypress, and has been popular in their gardens since first introduction
• Port Orford, OR was location of first ID by western botanists
• ~300 types or cultivars selected from this species, more than any other conifer

Ecology & Adaptations:

• small native range
  • seaward slopes in a coastal belt along Pacific Coast mountain ranges from Coos Bay in southwestern Oregon to the Klamath River in northwestern California, with isolated populations in northern California at higher elevations (<1700 m.)
  • northern distribution is limited by frost
• cool Mediterranean climate (warm, dry summers and cool, wet winters) with summer fog, from which it is able to capture moisture on branchlets
• inland, found on moist sites (seeps, stream channels, bogs) or locations with lots of precipitation
• sandy and clay loams and rocky ridges
• adapted to ultramafic soils with high metal content
  • compounds in sapwood (phloem) bind with metal ions, which prevents them from catalyzing damaging oxidation reactions within the tissues.
• very shade tolerant
  • slow growth rates
  • shaded individuals often take on a shrubby form, without a strong vertical leader (trunk)
• pollination by wind
• seed dispersal:
  • usually within 1-3 tree heights
  • small wings help the seed be carried by wind and float on water, which may be important in stream-side habitats
  • produces abundant seed which enables seedling establishment under forest stands, which creates multi- aged stands
• vegetative reproduction:
  • shallow root system makes species susceptible to windthrow, but layering (re-rooting from stems touching the ground) occurs in downed trees
• mature trees are fire resistant due in part to bark that can be as thick as 10 inches
  • surviving trees provide seed source for new growth in burned areas
• compounds in plant tissues defend against microbial (bacterial and fungal) infections